Theoretical Model for the Power Recovery Optimization in Natural Gas Distribution Networks: Colombian Case

Abstract

LNG production used in passenger transport systems obtained trough natural gas expansion in city networks is a novel process and it has been demonstrated its small energy consumption. This process has made in two stages: first one consist of a pressure reduction and the second one in a cryogenic liquefaction. This paper is focused in the first stage and in a second paper the author will present the simulation result of LNG production optimization for urban transportation systems. This research has been supported by Colombian Science and Technology National Agency (Colciencias, in Spanish) and the company Terpel. As before mention, in natural gas distribution networks, this fuel is transported at high pressures through long length pipelines between the source and final consumers. In every place of consumption or at passing into a lower pressure pipeline the gas pressure must be reduced. Commonly, high pressure is achieved by using a number of compressors, each one attached to a natural gas combustion turbine, consuming energy, and gas pressure reduction is accomplished in mechanical letdown-valves, where an isenthalpic expansion takes place without any energy production. A few amount of the energy consumed could be recovered taking advantage of the enthalpy drop in delivery sites or in pressure reduction stations by the